HIBERNATION. 309 



years when the worms were very numerous we should expect to find 

 them infesting cotton at a period earlier than that which we have des- 

 ignated, and where corn is not grown in the vicinity, they probably feed 

 upon cotton from the first appearance of the flower-buds. These points 

 will account for the fact of the frequent early reports of the ravage of 

 the boll- worm in cotton. 



The same difficulty also arises in ascertaining the precise number of 

 broods of the boll-worm that was found with the cotton-worm. Some 

 moths issuing from winter quarters later than others, or failing so soon 

 to find a suitable place of deposit for their eggs, will lay their eggs later 

 than others. Some larvae, moreover, may, by surrounding circumstances, 

 fail to develop as fast as others. These and other points combined start 

 an irregularity of the broods, the tendency of which is to continually 

 increase rather than to diminish, until in the later generations upon cot- 

 ton we may find them in all four stages at once eggs, larvae of all sizes, 

 chrysalides, and moths. The number and relative appearances of the 

 broods normally, however, we believe to be that which we have given. 



The boll- worm disappears in the fall before the cotton-worm does. 

 Mr. GL W. Smith-Vaniz, of Canton, Miss., gathered eggs from one of 

 which a larva hatched August 30. It became a chrysalis September 22, 

 and passedthe winter in this state, issuing as a moth May 14. Another 

 brood of the cotton-caterpillars was reared after this boll-worm went 

 into winter quarters. 



In his Third Missouri Entomological Eeport, p. 107, Professor Eiley 

 makes the statement: 



Most of the inotha issue in the fall and hibernate as such, but some of them pass the 

 winter in the chrysalis state and do not issue till the following spring. I have known 

 them to issue, in this latitude (38 N. ), after the 1st of November, when no frost had 

 previously occurred. 



It may be true that Heliotliis occasionally hibernates as a moth. No 

 instance of such hibernation has, however, come under our notice, nor 

 do we find any other statement of this fact than this of Professor Eiley's, 

 just quoted. It is certain that the insect normally hibernates in the 

 chrysalis state, and that if a hibernating moth is found it is an excep- 

 tional occurrence. 



Many of the noctuida? hibernate as moths, and some, as, for instance, 

 the army worm of the north (HeliopMla unipuncta, Haworth), are sup- 

 posed to winter either in the moth or chrysalis state. The latter point 

 is not yet definitely settled, however, and even if it were it would 

 simply create a precedent, not necessarily a probability, in favor of a 

 dual hibernation of Heliothis. 



INFLUENCE OF WEATHER. 



It seems to be a pretty generally-settled point among planters, so far 

 as we can ascertain, that the boll-worm is influenced by the weather in 

 a similar manner to Aletia; that is to say, that they flourish best in wet 



